Within the class of vitamins, several have recommended daily allowances (RDA) in the area of micrograms per day and are defined as micronutrients. Examples of some micronutrients are Vitamin B12 which has an RDA of 1.5 to 12.0 .mu.g/day; folic acid has an RDA of 100 to 800 .mu.g/day; and biotin which has an RDA of 75 to 300 .mu.g/day. The proper distribution of these micronutrients in tablets or other vehicles of administration like foods is a difficult task unless special steps are taken to reduce the crystal size and serially dilute the active substance prior to or during the manufacture of the end product.
U.S. Pat. No. 5,000,888 to Killbride et al. discloses spray-drying a riboflavin slurry. The slurry is comprised of 10-50 parts riboflavin, 0.5-15 parts of a binder, and 50-75 parts of water, such that the mixture contains 40-75 weight % water. In an example, the process yielded a final composition containing 94 weight % riboflavin, 5 weight % binder, and 1 weight % water.
Kilbride (U.S. Pat. No. 4,994,458) teaches a riboflavin composition made via a rotary fluidized bed granulator. The product of the process comprises about 70-99.5 weight % riboflavin, and 0.5-25 weight % binder.
Schmidt et al. (U.S. Pat. No. 4,533,674) teach a process for preparing a powder containing 90 weight % ascorbic acid, less than 9 weight % binder, 0.2-2 weight % silicon dioxide, and 0.2-5 weight % lubricant. Densifying agents are not included in the compositions.
Ono, et al., (EP 416,773) describe a vitamin B12 composition dispersed in a mixture of starch and dextrin. The dextrin and starch are mixed together, and an aqueous solution of vitamin B12 is added to form a slurry, which then is spray dried to form the composition. The vitamin B12 is present in the dried composition at about 0.5-1.0 weight %, and the dextrin is present at about 5-30 weight % based on the total weight of B12, dextrin and starch in the composition.
Cannalonga et al. (U.S. Pat. No. 3,914,430) teach a spray drying technique for preparing agglomerated powders. The technique involves the introduction of an absorbent material, e.g., dicalcium phosphate, into the spray drying chamber with an emulsion of water, vitamin and hydrolyzed gelatin. The absorbent particles are coated onto the emulsion ingredients to form the agglomerates. Examples of resulting products therefrom include vitamin E encapsulated in hydrolyzed gelatin, vitamin A encapsulated in hydrolyzed gelatin, vitamin A encapsulated in gum acacia, vitamin D encapsulated in hydrolyzed gelatin, and riboflavin encapsulated in maltrin. The resulting powders have 40-60 weight % vitamin, 1-5 weight % absorbent, and 35-59 weight % gelatin.
Cavalli et al. (U.S. Pat. No. 3,396,226) teach dry-mixed compositions containing up to about 80 weight % ascorbic acid, up to about 50 weight % microcrystalline cellulose, and from 0.07-5.0 weight % of a lubricant, e.g., calcium stearate.
Stoyle et al. (U.S. Pat. No. 3,293,132) disclose compositions containing 75-95 weight % ascorbic acid, 5-25 weight % carbohydrate, e.g., sugars or starches, and 0.5-7 weight % binder, e.g., gelatins. The compositions are prepared by dissolving the carbohydrate and binder in water, adding the ascorbic acid to form a slurry having 40-60 weight % solids, spray-drying the slurry, and then adding a lubricant to form the product.
Schmidt et al. (WO 85/01877) teach compositions containing at least 80 weight % of a water-soluble vitamin, less than 15 weight % of a binder, e.g., gelatins; 0.2-2 weight % adsorbent, e.g., silicon dioxide; 0.2-5 weight % lubricant, e.g., stearic acid; and less than 3 weight % of other excipients, e.g., sugars, starch, etc. The compositions are prepared by spray-drying an aqueous slurry of a water-soluble vitamin and a binder, in the presence of a lubricant and adsorbent.